Availability
of
different nuclear reactions (fusion of stable and radioactive
nuclei,
multi-nucleon transfers and neutron capture) for production of
new isotopes of
superheavy elements (SH) will be discussed in the talk.Low values of the
fusion cross sections and
very short half-lives of nuclei with Z>120 put obstacles in
synthesis of new
elements. However
the fusion reactions
of medium mass projectiles with different actinide targets still
can be used
for the production of the not-yet-synthesized SH nuclei. The gap of unknown SH
nuclei, located between
the isotopes which were produced earlier in the cold and hot
fusion reactions,
could be filled in fusion reactions of 48Ca with
available lighter
isotopes of Pu, Am, and Cm.Cross
sections for the production of these nuclei are predicted to be
rather large,
and the corresponding experiments can be easily performed at
existing
facilities.The use
of heavier actinide
targets give us a chance to produce more neutron enriched SH
isotopes. Moreover,
for the first time, a narrow pathway
is found to the middle of the island of stability owing to
possible beta(+)
decay of SH isotopes which can be formed in ordinary fusion
reactions of stable
nuclei. Multi-nucleon
transfer processes
at near barrier collisions of heavy (and very heavy, U-like)
ions seem to be
quite realistic reaction mechanism allowing us to produce new
neutron enriched
heavy nuclei located in the unexplored upper part of the nuclear
map. The predicted
cross sections, the angular and
energy distributions of primary and survived reaction products
should be useful
for the design of appropriate experimental equipment and for
carrying out
experiments of such kind.Neutron
capture
reactions can be also used for the production of the long-living
neutron rich SH nuclei.Strong
neutron
fluxes might be provided by pulsed nuclear reactors and by
nuclear explosions
in laboratory conditions and by supernova explosions in nature.
All these
possibilities will be discussed in
the talk.